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postgresql/src/include/rewrite/rewriteManip.h

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Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
/*-------------------------------------------------------------------------
*
Change my-function-name-- to my_function_name, and optimizer renames.
1999-02-14 00:22:53 +01:00
* rewriteManip.h
Remove some dead code, simplify calling convention.
2001-06-13 20:56:30 +02:00
* Querytree manipulation subroutines for query rewriter.
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
*
Update copyright for the year 2010.
2010-01-02 17:58:17 +01:00
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
Add: * Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files.
2000-01-26 06:58:53 +01:00
* Portions Copyright (c) 1994, Regents of the University of California
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
Update copyright for the year 2010.
2010-01-02 17:58:17 +01:00
* $PostgreSQL: pgsql/src/include/rewrite/rewriteManip.h,v 1.52 2010/01/02 16:58:08 momjian Exp $
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
*
*-------------------------------------------------------------------------
*/
Massive commit to run PGINDENT on all *.c and *.h files.
1997-09-07 07:04:48 +02:00
#ifndef REWRITEMANIP_H
#define REWRITEMANIP_H
Postgres95 1.01 Distribution - Virgin Sources
1996-07-09 08:22:35 +02:00
Remove some dead code, simplify calling convention.
2001-06-13 20:56:30 +02:00
#include "nodes/parsenodes.h"
Cleanup up include files.
1997-11-26 02:14:33 +01:00
Fix subquery pullup to wrap a PlaceHolderVar around the entire RowExpr that's generated for a whole-row Var referencing the subquery, when the subquery is in the nullable side of an outer join. The previous coding instead put PlaceHolderVars around the elements of the RowExpr. The effect was that when the outer join made the subquery outputs go to null, the whole-row Var produced ROW(NULL,NULL,...) rather than just NULL. There are arguments afoot about whether those things ought to be semantically indistinguishable, but for the moment they are not entirely so, and the planner needs to take care that its machinations preserve the difference. Per bug #5025. Making this feasible required refactoring ResolveNew() to allow more caller control over what is substituted for a Var. I chose to make ResolveNew() a wrapper around a new general-purpose function replace_rte_variables(). I also fixed the ancient bogosity that ResolveNew might fail to set a query's hasSubLinks field after inserting a SubLink in it. Although all current callers make sure that happens anyway, we've had bugs of that sort before, and it seemed like a good time to install a proper solution. Back-patch to 8.4. The problem can be demonstrated clear back to 8.0, but the fix would be too invasive in earlier branches; not to mention that people may be depending on the subtly-incorrect behavior. The 8.4 series is new enough that fixing this probably won't cause complaints, but it might in older branches. Also, 8.4 shows the incorrect behavior in more cases than older branches do, because it is able to flatten subqueries in more cases.
2009-09-02 19:52:24 +02:00
typedef struct replace_rte_variables_context replace_rte_variables_context;
typedef Node * (*replace_rte_variables_callback) (Var *var,
replace_rte_variables_context *context);
struct replace_rte_variables_context
{
replace_rte_variables_callback callback; /* callback function */
void *callback_arg; /* context data for callback function */
int target_varno; /* RTE index to search for */
int sublevels_up; /* (current) nesting depth */
bool inserted_sublink; /* have we inserted a SubLink? */
};
Clean up rewriter routines to use expression_tree_walker and expression_tree_mutator rather than ad-hoc tree walking code. This shortens the code materially and fixes a fair number of sins of omission. Also, change modifyAggrefQual to *not* recurse into subselects, since its mission is satisfied if it removes aggregate functions from the top level of a WHERE clause. This cures problems with queries of the form SELECT ... WHERE x IN (SELECT ... HAVING something-using-an-aggregate), which would formerly get mucked up by modifyAggrefQual. The routine is still fundamentally broken, of course, but I don't think there's any way to get rid of it before we implement subselects in FROM ...
1999-10-01 06:08:24 +02:00
extern void OffsetVarNodes(Node *node, int offset, int sublevels_up);
extern void ChangeVarNodes(Node *node, int old_varno, int new_varno,
Ye-old pgindent run. Same 4-space tabs.
2000-04-12 19:17:23 +02:00
int sublevels_up);
Fix some (more) problems with subselects in rules. Rewriter failed to mark query as having subselects if a subselect was added from a rule WHERE condition (as opposed to a rule action). Also, fix adjustment of varlevelsup so that it actually has some prospect of working when inserting an expression containing a subselect into a subquery.
2000-03-16 04:23:18 +01:00
extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
Ye-old pgindent run. Same 4-space tabs.
2000-04-12 19:17:23 +02:00
int min_sublevels_up);
Fix pull_up_simple_union_all to copy all rtable entries from child subquery to parent, not only those with RangeTblRefs. We need them in ExecCheckRTPerms. Report by Brendan O'Shea. Back-patch to 8.2, where pull_up_simple_union_all was introduced.
2008-08-14 22:31:29 +02:00
extern void IncrementVarSublevelsUp_rtable(List *rtable,
8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list provided by Andrew.
2009-06-11 16:49:15 +02:00
int delta_sublevels_up, int min_sublevels_up);
First cut at full support for OUTER JOINs. There are still a few loose ends to clean up (see my message of same date to pghackers), but mostly it works. INITDB REQUIRED!
2000-09-12 23:07:18 +02:00
extern bool rangeTableEntry_used(Node *node, int rt_index,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
int sublevels_up);
First cut at full support for OUTER JOINs. There are still a few loose ends to clean up (see my message of same date to pghackers), but mostly it works. INITDB REQUIRED!
2000-09-12 23:07:18 +02:00
extern bool attribute_used(Node *node, int rt_index, int attno,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
int sublevels_up);
First cut at full support for OUTER JOINs. There are still a few loose ends to clean up (see my message of same date to pghackers), but mostly it works. INITDB REQUIRED!
2000-09-12 23:07:18 +02:00
Repair breakage of rules containing INSERT ... SELECT actions, per bug report from Joel Burton. Turns out that my simple idea of turning the SELECT into a subquery does not interact well *at all* with the way the rule rewriter works. Really what we need to make INSERT ... SELECT work cleanly is to decouple targetlists from rangetables: an INSERT ... SELECT wants to have two levels of targetlist but only one rangetable. No time for that for 7.1, however, so I've inserted some ugly hacks to make the rewriter know explicitly about the structure of INSERT ... SELECT queries. Ugh :-(
2000-12-05 20:15:10 +01:00
extern Query *getInsertSelectQuery(Query *parsetree, Query ***subquery_ptr);
Clean up rewriter routines to use expression_tree_walker and expression_tree_mutator rather than ad-hoc tree walking code. This shortens the code materially and fixes a fair number of sins of omission. Also, change modifyAggrefQual to *not* recurse into subselects, since its mission is satisfied if it removes aggregate functions from the top level of a WHERE clause. This cures problems with queries of the form SELECT ... WHERE x IN (SELECT ... HAVING something-using-an-aggregate), which would formerly get mucked up by modifyAggrefQual. The routine is still fundamentally broken, of course, but I don't think there's any way to get rid of it before we implement subselects in FROM ...
1999-10-01 06:08:24 +02:00
extern void AddQual(Query *parsetree, Node *qual);
Rule rewriter was doing the wrong thing with conditional INSTEAD rules whose conditions might yield NULL. The negated qual to attach to the original query is properly 'x IS NOT TRUE', not 'NOT x'. This fix produces correct behavior, but we may be taking a performance hit because the planner is much stupider about IS NOT TRUE than it is about NOT clauses. Future TODO: teach prepqual, other parts of planner how to cope with BooleanTest clauses more effectively.
2002-10-20 02:58:55 +02:00
extern void AddInvertedQual(Query *parsetree, Node *qual);
1) Queries using the having clause on base tables should work well now. Here some tested features, (examples included in the patch): 1.1) Subselects in the having clause 1.2) Double nested subselects 1.3) Subselects used in the where clause and in the having clause simultaneously 1.4) Union Selects using having 1.5) Indexes on the base relations are used correctly 1.6) Unallowed Queries are prevented (e.g. qualifications in the having clause that belong to the where clause) 1.7) Insert into as select 2) Queries using the having clause on view relations also work but there are some restrictions: 2.1) Create View as Select ... Having ...; using base tables in the select 2.1.1) The Query rewrite system: 2.1.2) Why are only simple queries allowed against a view from 2.1) ? 2.2) Select ... from testview1, testview2, ... having...; 3) Bug in ExecMergeJoin ?? Regards Stefan
1998-07-19 07:49:26 +02:00
Arrange to convert EXISTS subqueries that are equivalent to hashable IN subqueries into the same thing you'd have gotten from IN (except always with unknownEqFalse = true, so as to get the proper semantics for an EXISTS). I believe this fixes the last case within CVS HEAD in which an EXISTS could give worse performance than an equivalent IN subquery. The tricky part of this is that if the upper query probes the EXISTS for only a few rows, the hashing implementation can actually be worse than the default, and therefore we need to make a cost-based decision about which way to use. But at the time when the planner generates plans for subqueries, it doesn't really know how many times the subquery will be executed. The least invasive solution seems to be to generate both plans and postpone the choice until execution. Therefore, in a query that has been optimized this way, EXPLAIN will show two subplans for the EXISTS, of which only one will actually get executed. There is a lot more that could be done based on this infrastructure: in particular it's interesting to consider switching to the hash plan if we start out using the non-hashed plan but find a lot more upper rows going by than we expected. I have therefore left some minor inefficiencies in place, such as initializing both subplans even though we will currently only use one.
2008-08-22 02:16:04 +02:00
extern bool contain_aggs_of_level(Node *node, int levelsup);
Add a bunch of new error location reports to parse-analysis error messages. There are still some weak spots around JOIN USING and relation alias lists, but most errors reported within backend/parser/ now have locations.
2008-09-01 22:42:46 +02:00
extern int locate_agg_of_level(Node *node, int levelsup);
Support window functions a la SQL:2008. Hitoshi Harada, with some kibitzing from Heikki and Tom.
2008-12-28 19:54:01 +01:00
extern int locate_windowfunc(Node *node);
Fix some (more) problems with subselects in rules. Rewriter failed to mark query as having subselects if a subselect was added from a rule WHERE condition (as opposed to a rule action). Also, fix adjustment of varlevelsup so that it actually has some prospect of working when inserting an expression containing a subselect into a subquery.
2000-03-16 04:23:18 +01:00
extern bool checkExprHasAggs(Node *node);
Support window functions a la SQL:2008. Hitoshi Harada, with some kibitzing from Heikki and Tom.
2008-12-28 19:54:01 +01:00
extern bool checkExprHasWindowFuncs(Node *node);
Fix some (more) problems with subselects in rules. Rewriter failed to mark query as having subselects if a subselect was added from a rule WHERE condition (as opposed to a rule action). Also, fix adjustment of varlevelsup so that it actually has some prospect of working when inserting an expression containing a subselect into a subquery.
2000-03-16 04:23:18 +01:00
extern bool checkExprHasSubLink(Node *node);
Fix subquery pullup to wrap a PlaceHolderVar around the entire RowExpr that's generated for a whole-row Var referencing the subquery, when the subquery is in the nullable side of an outer join. The previous coding instead put PlaceHolderVars around the elements of the RowExpr. The effect was that when the outer join made the subquery outputs go to null, the whole-row Var produced ROW(NULL,NULL,...) rather than just NULL. There are arguments afoot about whether those things ought to be semantically indistinguishable, but for the moment they are not entirely so, and the planner needs to take care that its machinations preserve the difference. Per bug #5025. Making this feasible required refactoring ResolveNew() to allow more caller control over what is substituted for a Var. I chose to make ResolveNew() a wrapper around a new general-purpose function replace_rte_variables(). I also fixed the ancient bogosity that ResolveNew might fail to set a query's hasSubLinks field after inserting a SubLink in it. Although all current callers make sure that happens anyway, we've had bugs of that sort before, and it seemed like a good time to install a proper solution. Back-patch to 8.4. The problem can be demonstrated clear back to 8.0, but the fix would be too invasive in earlier branches; not to mention that people may be depending on the subtly-incorrect behavior. The 8.4 series is new enough that fixing this probably won't cause complaints, but it might in older branches. Also, 8.4 shows the incorrect behavior in more cases than older branches do, because it is able to flatten subqueries in more cases.
2009-09-02 19:52:24 +02:00
extern Node *replace_rte_variables(Node *node,
int target_varno, int sublevels_up,
replace_rte_variables_callback callback,
void *callback_arg,
bool *outer_hasSubLinks);
extern Node *replace_rte_variables_mutator(Node *node,
replace_rte_variables_context *context);
Subselects in FROM clause, per ISO syntax: FROM (SELECT ...) [AS] alias. (Don't forget that an alias is required.) Views reimplemented as expanding to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually work now (he says optimistically). No UNION support in subselects/views yet, but I have some ideas about that. Rule-related permissions checking moved out of rewriter and into executor. INITDB REQUIRED!
2000-09-29 20:21:41 +02:00
extern Node *ResolveNew(Node *node, int target_varno, int sublevels_up,
Change expandRTE() and ResolveNew() back to taking just the single RTE of interest, rather than the whole rangetable list. This makes the API more understandable and avoids duplicate RTE lookups. This patch reverts no-longer-needed portions of my patch of 2004-08-19.
2005-06-04 21:19:42 +02:00
RangeTblEntry *target_rte,
Fix subquery pullup to wrap a PlaceHolderVar around the entire RowExpr that's generated for a whole-row Var referencing the subquery, when the subquery is in the nullable side of an outer join. The previous coding instead put PlaceHolderVars around the elements of the RowExpr. The effect was that when the outer join made the subquery outputs go to null, the whole-row Var produced ROW(NULL,NULL,...) rather than just NULL. There are arguments afoot about whether those things ought to be semantically indistinguishable, but for the moment they are not entirely so, and the planner needs to take care that its machinations preserve the difference. Per bug #5025. Making this feasible required refactoring ResolveNew() to allow more caller control over what is substituted for a Var. I chose to make ResolveNew() a wrapper around a new general-purpose function replace_rte_variables(). I also fixed the ancient bogosity that ResolveNew might fail to set a query's hasSubLinks field after inserting a SubLink in it. Although all current callers make sure that happens anyway, we've had bugs of that sort before, and it seemed like a good time to install a proper solution. Back-patch to 8.4. The problem can be demonstrated clear back to 8.0, but the fix would be too invasive in earlier branches; not to mention that people may be depending on the subtly-incorrect behavior. The 8.4 series is new enough that fixing this probably won't cause complaints, but it might in older branches. Also, 8.4 shows the incorrect behavior in more cases than older branches do, because it is able to flatten subqueries in more cases.
2009-09-02 19:52:24 +02:00
List *targetlist, int event, int update_varno,
bool *outer_hasSubLinks);
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 07:26:15 +01:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
#endif /* REWRITEMANIP_H */